#include <bits/stdc++.h>
using namespace std;

int main() {
    int cnt = 0;
    double s, now = 0.0, l = 2.0;
    cin >> s;
    while (now < s) {
        now += l;
        ++cnt;
        l *= 0.98;
    }
    cout << cnt;
    return 0;
}